Gaseous-discharge device



Dec. 29, 1959 s, GOLDBERG 2,919,372

GASEOUS'DISCHARGE DEVICE Filed June 1, 1956 Y 137 I A 3 29 399 27 3| |7 4-3 L' L l 2 3 TRIGGER IMPULSE INVENTOR.

SEYMOUR GOLDBERG A TTORNEYS GASEOUS-DISCHARGE DEVICE Seymour Goldberg, Lexington, Mass., assignor to Edgerton, Germeshausen 8; Grier, Inc., Boston, Mass, a corporation of Massachusetts Application June 1, 1956, Serial No. 588,905

22 Claims. (Cl. 313-307) The present invention relates to gaseous-discharge devices and, more particularly, to gaseous-discharge tubes of the thyratron type.

Gaseous-discharge devices, such as hydrogen thyratrons and the like, are frequently employed as switching de vices to permit voltages to be delivered to a load. Typical electrical systems embodying such switching devices are described, for example, in United States Letters Patent Nos. 2,518,879 and 2,592,556, issued, respectively, on August 15, 1950, and April 15, 1952, to Kenneth J. Germeshausen. In radar pulsing circuits and the like, energy is stored in a pulse-forming line or capacitor and is then discharged by operation of the switching device into a load, such as a magnetron tube. A voltage of polarity inverse to that usually appearing at the anode of such switching devices during their normal operation is frequently developed. This inverse voltage may appear, for example, under conditions where the load is sparking or otherwise intermittently shorting. Under such conditions, the inverse voltage can initiate a cumulative series of events which may result in the eventual destruction of the load or the gaseous-discharge switching device. Heretofore, separate vacuum-tube diode circuits or separate hydrogen thyratron clipper circuits have been used to remove or clip such inverse voltage in order to obviate such undesirable results.

An object of the present invention is to eliminate the necessity for such separate circuits by combining in a single envelope a gaseous-discharge switching tube and a clipper device for removing inverse voltage from the anode of the switching tube.

In summary, the gaseous-discharge device of the present invention contains within the gas of the device a plurality of spaced electrodes comprising a cathode, an anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the cathode and the anode. A further cathode is provided external to the said space cooperative with the anode to constitute a clipper'of voltage of polarity inverse to the anode voltage, and means is further provided for removing inverse-voltage current passed between the further cathode and the anode.

. A further object is to provide a new and improved gaseous-discharge device. I

An additional object is to provide a new and improved electrical apparatus embodying such a novel gaseousdischarge device in an electric circuit.

Other and further objects of the invention will be .explained hereinafter and will be more particularly pointed out in the appended claims.

The invention will now be explained in connection with the accompanying drawings, Fig. 1 of which is a longitudinal section of a gaseous-discharge device embodying the invention in preferred form; and

Fig. 2 is a circuit diagram of a preferred electric circuit for use with the device of Fig. 1.

Referring to Fig. l, a gaseous-discharge device 1 is provided with an anode electrode 9, a cathode electrode 11, a shield electrode '13, and a trigger control-grid electrode 15. The tube 1 may be filled with hydrogen or other gas at, for example 0.5 millimeter pressure, and may be enclosed by cylindrical ceramic side walls 3 and end walls 5 and 7. Alumina-insulating ceramic may be employed, such as the type COORS AI-200. The anode 9 may comprise a copper cup-shaped member the vertical walls of which are close to the lateral walls 3 of the tube 1 and the edges of which are provided with a flange 17 extending outside the tube between the inner and outer surfaces of the envelope walls 3. A solder seal 18, such as a silver-titanium-hydride-nickel bonding, may secure the flange 17 between the upper edge of the wall 3 and the peripheral region of the under surface of the upper envelope Wall 7. The shield electrode 13 may also assume the shape of a copper cup, though it is mounted inverted with its lateral edges close to the envelope side walls 3 and its flange 19 sealed, as before described, at 20, between the peripheral region of the bottom wall 5 of the envelope 1 and the lower edge of the side walls 3. The said flanges 17 and 19, extending external to the envelope 1, provide a means for conducting heat outside the envelope and provide, also, for electrical connections to the electrode structures. Heat is also dissipated to the ceramic side walls 3. The cathode 11 may be of the types described in the said Letters Patent, supported by cathode posts or pin supports '21, 23, passed through and sealed to the bottom wall 5 to permit the external application of cathode potential and heater current. Further details of similar tube elements are described in the copending application of Kenneth J. Germeshausen, Serial No. 598,425, entitled Gaseous-Discharge Device, filed on or about July 17, 1956.

In accordance with the present invention, the upper substantially planarsurface of the inverted cup-shaped shield electrode 13 is apertured, as at 25, in line With the centrally disposed control or trigger electrode 15 which, in turn, is supported by a pin support 27, also passed through and sealed to the bottom envelope wall 5. The lower substantially planar surface of the cup-shaped anode 9, on the other hand, is provided preferably with a pair of longitudinal slot apertures 27 and 29 disposed on either side of the central-shield aperture 25. A pair of longi tudinally extending second-cathode rods 31, 33 are depended from the upper envelope wall 7 by supports 35, 37 Within the anode cup in position above and substantially. parallel to the respective anode slot apertures 27 and 29 and hence extending in a direction at substantially right angles to the direction from the cathode 11 to the anode 9. Voltage for biasing the cathodes 31 and 33 may be supplied by the pins 35', 37' extending through and sealed to the upper envelope wall 7. The cathodes 31 and 33 are series-connected by the member 39 disposed substantially parallel to the bottom surface of the anode cup 9.

It is conducive to explanation of the operation of the tube of Fig. 1 to consider, the preferred circuit of Fig. 2. For purposes of illustration, this circuit represents a radar-type line modulator circuit employing an artificial pulse-forming voltage-storing line P comprising series inductors L L L etc. and shunt capacitors C C C etc. Voltage is stored in the line P from an oscillatory series-resonant charging circuit traceable from the terminal of a source of voltage such as a direct.- current or alternating-current voltage source, through a charging inductor L, acheck valve V, the line P, a load Z, such as a magnetron or other electric-discharge device or tube, to the terminal of the source, which maybe grounded as at 41. Such a circuit will store a voltage greater than the voltage of the source (theoretically twice the voltage) in the line P, in'viewof its oscillatory character, as described in United States .Letters Patented Dec. 29, 1959,

& Patent No. 2,478,907, issued August 16, 1949, to Harold E. Edgerton. The anode 9 of the tube 1 is connected at 43 to the junction between the check valve V and the line P, and the cathode 11 is connected to the ground terminal 41.

At the desired moment, a trigger pulse is applied between the control or trigger electrode 15 and the cathode 11 of the tube 1 to render the tube conductive between its cathode 11 and anode 9, thereby to discharge the voltage stored in the line P through the load Z in the discharge circuit comprising the line P, the load Z and the tube 1. The tube thus functions in the normal manner as a thyratron switching device. By applying an appropriative negative bias B between the second or upper cathodes 31, 33 and the anode 9, should an undesired negative voltage or voltage inverse to that at the anode 9 during operation of the circuit appear at the anode 9, conduction will also take place from the cathodes 31, 33 through the anode slots 27, 29 to the shield electrode 13 and thence by conductor 47 to the ground terminal 41. This path will therefore serve to clip, short-circuit or remove such undesired inverse voltage without interfering with the thyratron operation of the tube 1.

Aside from the convenience and simplicity of the construction of the present invention, the use of the gaseousconduction clipping section within the thyratron envelope is highly desirable in view of the low impedance of the clipper which assures very rapid removal of inverse voltage. Many arrangements of negative bias B upon the clipper portion of the tube 1, moreover, may be employed to achieve any desired breakdown properties in the inverse direction. The shield grid 13, furthermore, need not be connected directly to ground potential but may be maintained near ground or chassis potential.

Further modifications will occur to those skilled in the art and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

'What is claimed is:

1. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means for removing inverse-voltage current passed between the second cathode and the anode.

2. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes conprising a first cathode, an anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode for removing inverse-voltage current passed between the second cathode and the anode.

3. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an apertured anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with re apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode disposed in the said space adjacent the anode aperture -f.0r removing inverse-voltage current passed between the second cathode and the anode.

4. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a-first cathode, an apertured anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising an apertured shield electrode disposed in the said space between the control electrode and the anode adjacent the anode aperture for removing inverse-voltage current passed between the second cathode and the anode, the aperture of the shield electrode being aligned with the control electrode.

5. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an apertured anode having a substantially planar surface and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode having a substantially planar surface disposed in the said space adjacent the anode aperture for removing inverse-voltage current passed between the second cathode and the anode.

6. A gaseous-discharge device containing within the gas of the device a plurality or" spaced electrodes comprising a first cathode, a cup-shaped apertured anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and within the cup of the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising an inverted cupshaped electrode disposed in the said space adjacent the anode aperture for removing inverse-voltage current passed between the second cathode and the anode.

7. A gaseous-discharge device containing Within the gas of the device a plurality of spaced electrodes comprising a first cathode, an apertured anode having a substantially planar surface and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a shield electrode having a substantially planar apertured surface disposed in the said space between the control electrode and the anode adjacent the anode aperture for removing inverse-voltage current passed between the second cathode and the anode, the aperture of the shield electrode being aligned with the control electrode.

8. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, a cup-shaped apertured anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and cooperative with the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising an inverted cupshaped apertured shield electrode disposed in the said space between the control electrode and the anode adjacent the anode aperture for removing inverse-voltage current passed between the second cathode and the anode, the aperture of the shield electrode being aligned with the control electrode.

. 9. A gaseousdischarge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode having a pair of spaced apertures and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a pair of further cathode elements external to the said space and cooperative with the anode apertures to constitute a clipper of voltage of polarity inverse to the anode voltage, and means for removing inverse-voltage current passed from the second cathode through the anode apertures.

10. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode having a pair of spaced apertures and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a pair of further cathode elements external to the said space and cooperativewith the anode apertures to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode for removing inverse-voltage current passed from the second cathode through the anode apertures.

11. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, a cup-shaped anode having a pair of apertures and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a pair of further cathode elements external to the said space and within the cup, the elements being alined with the anode apertures to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising an inverted cup-shaped apertured electrode disposed in the said space between the control electrode and the anode for removing inverse-voltage current passed from the cathode elements through the anode apertures, the aperture of the inverted cup-shaped electrode being disposed between the pair of anode apertures and in alignment with the control electrode.

12. A gaseous-discharge device as claimed in claim 11 and in which the gas is hydrogen and the device is provided with a ceramic envelope between the inner and outer walls of which flange edges of the cup-shaped anode and the inverted cup-shaped electrode are secured.

13. A gaseous-discharge device as claimed in claim 11 and in which the pair of anode apertures are longitudinal slots and the cathode elements extend longitudinally substantially parallel to the slots.

14. Apparatus of the character described having, in

combination, a gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode and a control electrode, an electrical circuit for supplying voltage between the anode and the first cathode, means for supplying a trigger impulse to the control electrode for initiating a discharge of the said voltage through the space between the first cathode and the anode, the gaseous-discharge device having a second cathode external to the said space and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, means for biasing the clipper to conduct upon the advent of such voltage of inverse polarity, further electrode means disposed Within the gaseous discharge device for receiving inverse-voltage current passed between the second cathode and the anode, and means for connecting the further electrode means into circuit to short-circuit such inverse-voltage current received by the further electrode means.

15. Apparatus of the character described having, in combination, a gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an apertured anode and a control electrode, an electrical circuit for supplying voltage between the anode and the first cathode, means for supplying a trigger impulse to the control electrode for initiating a discharge of the said voltage through the space between the first cathode and the anode, the gaseous-discharge device having a second cathode external to the said space and aligned with the aperture of the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, means for biasing the clipper to conduct upon the advent of such voltage of in- 6 verse polarity, further electrode means disposed within the'gaseous-discharge device for receiving inverse-voltage current passed between the second cathode and the anode, and means for connecting the further electrode means into circuit to short-circuit such inverse-voltage current received by the further electrode means.

16. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode and a control electrode for initating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and adjacent and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means for removing inverse-voltage current passed between the second cathode and the anode.

17. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and adjacent and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode disposed between the control electrode and the anode for removing inverse-voltage current passed between the second cathode and the anode.

18. A gaseous-discharge de'vice containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an apertured anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and adjacent an aperture of the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode disposed in the said space adjacent the said anode aperture for removing inverse-voltage current passed between the second cathode and the anode.

19. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an apertured anode and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and adjacent an aperture of the apertured anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising an apertured electrode disposed in the said space between the control electrode and the anode for removing inverse voltage current passed between the second cathode and the anode, the aperture of the apertured electrode being substantially aligned with the control electrode.

20. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode having at least one aperture disposed to the side of the central portion thereof and a control electrode for initiating a discharge of voltage developed at the anode through the space between the first cathode and the anode, a second cathode external to the said space and adjacent the said aperture of the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode disposed in the said space adjacent the said anode aperture for removing inverse-voltage current passed between the second cathode and the anode.

21. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode and a control electrode for initiating a discharge of voltage developed at the anode in the direction through the space between the first cathode and the anode, a second cathode external to the said space extending at an angle to the said direction and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means for removing inverse-voltage current passed between the second cathode and the anode.

22. A gaseous-discharge device containing within the gas of the device a plurality of spaced electrodes comprising a first cathode, an anode and a control electrode for initiating a discharge of voltage developed at the anode in the direction through the space between the first cathode and the anode, a second cathode external to the said space extending at substantially a right angle to the said direction and cooperative with the anode to constitute a clipper of voltage of polarity inverse to the anode voltage, and means comprising a further electrode for removing inverse-voltage current passed between the second cathode and the anode.

References Cited in the file of this patent UNITED STATES PATENTS 1,418,022 Reisz May 30, 1922 2,292,382 Le Van Aug. 11, 1942 2,611,880 Webster Sept. 23, 1952 2,660,685 Johnson Nov. 24, 1953 2,770,751 Prager Nov. 13, 1956 2,793,313 Webster May 21, 1957 

